How would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle?

• A. Skeletal muscle would contract and relax normally, as acetylcholinesterase is not required for muscle function.
• B. Skeletal muscle would become unresponsive to nerve impulses due to rapid degradation of acetylcholine.
• C. Skeletal muscle would remain contracted due to continuous stimulation by acetylcholine.
• D. Skeletal muscle would be unable to contract because acetylcholine would not be released.

Answer: (C)

Verified step by step guidance

1. Understand the role of acetylcholinesterase: Acetylcholinesterase is an enzyme located at the motor end plate of neuromuscular junctions. Its primary function is to break down acetylcholine, a neurotransmitter, after it has been released into the synaptic cleft. This breakdown stops the stimulation of the muscle fiber, allowing it to relax.
2. Analyze the effect of acetylcholinesterase loss: Without acetylcholinesterase, acetylcholine would not be degraded efficiently. This would result in acetylcholine continuously stimulating the receptors on the muscle fiber, leading to prolonged contraction.
3. Consider the physiological consequences: Continuous stimulation by acetylcholine would prevent the muscle from relaxing, causing a state of sustained contraction known as tetany. This could impair normal muscle function and lead to muscle fatigue or damage.
4. Eliminate incorrect options: Review the provided choices and eliminate those that contradict the role of acetylcholinesterase. For example, the option stating that skeletal muscle would contract and relax normally is incorrect because acetylcholinesterase is essential for stopping contraction.
5. Select the correct answer: Based on the analysis, the correct answer is that skeletal muscle would remain contracted due to continuous stimulation by acetylcholine, as the loss of acetylcholinesterase prevents the breakdown of acetylcholine.